Aqueous mixed electrolyte and application thereof in zinc ion hybrid supercapacitor

Abstract

The invention relates to an aqueous mixed electrolyte and an application thereof in a zinc ion mixed supercapacitor. The invention discloses a mixed electrolyte taking organic zinc salt as a solute and water and ethylene glycol as solvents. The mixed electrolyte has ionic conductivity equivalent to that of an aqueous solution and a lower freezing point (less than -20 DEG C). The ethylene glycol interacts with anions in the organic zinc salt, so that the solvation state of zinc ions in the mixed electrolyte is changed, the electron cloud density of hydrogen in the zinc ion hydration structure is reduced, the hydrogen evolution reaction is effectively inhibited, the potential window of the hydrogen evolution reaction is widened, and the influence of gas production of the aqueous battery on the cycling stability is relieved. The adsorption effect of zinc ions on the surface of the activated carbon is enhanced, a faster and more efficient adsorption and desorption reaction can occur on the surface of the activated carbon, and the specific capacity of the hybrid supercapacitor is improved. The introduction of ethylene glycol and the organic zinc salt can greatly improve the conductivity of the mixed electrolyte at low temperature, thereby improving the power density of the hybrid supercapacitor at low temperature, and further widening the working temperature and application range of the hybrid supercapacitor.

Description

technical field [0001] The invention relates to the field of electrochemical energy storage, in particular to an aqueous mixed electrolyte and its application in a zinc ion mixed supercapacitor. Background technique [0002] With the development of smart electronic devices, electric vehicles and other fields, people have higher and higher requirements for energy density, fast charging and discharging performance and safety performance of energy storage devices. Zinc-ion secondary battery is a new type of high-efficiency rechargeable battery based on resource-rich zinc (theoretical specific capacity is 823mAh g) -1 ) instead of lithium sodium as the negative electrode material, not only the preparation process is simple, the battery material is non-toxic and inexpensive, the discharge process is safe, and at the same time, it has a high energy density. The cathode materials reported in the existing literature that can be used for free intercalation and deintercalation of zin...

AI Technical Summary

Problems solved by technology

However, due to the high freezing point of water, the system cannot operate at lower temperatures. Adding organic solvents and using organic zinc salts as solutes to construct a mixed electrolyte with a low freezing point is essential for improving the low-temperature performance of zinc-ion hybrid supercapacitors. important

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